Scrapers and other earth moving apparatuses of the general type to which the present invention relates are known. Representative examples of earth moving scrapers include, without limitation, the scrapers disclosed in U.S. Pat. No. 4,383,380, U.S. Pat. Nos. 4,388,769, 4,398,363, 4,553,608 and U.S. Pat. No. 6,347,670 to Miskin, the disclosures of which are each incorporated herein by reference. A typical scraper includes a frame having a front end, two opposing sides and at least two wheels connected to the opposing sides. A bucket for holding earth is connected to the frame. The bucket includes a floor, a rear wall, two upstanding opposing side walls, an open front and an open top. An apron, or gate, is located opposite the rear wall of the bucket and can swing closed to hold the soil in the bucket during transport. A blade is located adjacent the front edge of the floor of the bucket and cuts the earth to a predetermined depth as the earth moving apparatus is moved forward over the earth's surface. The soil cut from the earth by the blade is collected in the bucket. When the bucket is full of soil, the scraper is transported to another location where the soil is deposited.
The scraper or earth moving apparatus typically has an elongated tongue attached to the frame. The tongue is connected to a tractor that tows the scraper or the earth moving apparatus. The tongue may be connected to a tractor with a hitch or the tongue may be a so-called rigid, gooseneck that pivots and is attached to the tractor. Alternatively, the scraper may include a front set of “dolly” wheels or may be attached to a separate dolly that attaches to a tractor. Other scrapers or other earth moving apparatuses are self-propelled.
The soil is removed from the bucket in different ways. For instance, moving back scrapers, sweep scrapers, open bottom scrapers and dump scrapers are known. An ejector scraper has a moving wall or ejection assembly that pushes the soil out of the bucket. An example of an ejector scraper is disclosed in U.S. Pat. No. 6,041,528 assigned to Harvey Mfg. Corp. An example of a sweep scraper is an elevating type scraper that discharges soil collected in the bucket by moving members, or slats, across the floor of the bucket. An exemplary sweep scraper is disclosed in U.S. Pat. No. 3,934,360 assigned to Westinghouse Air Brake Company. In a dump scraper, the bucket of the scraper is tilted to dump the soil out of an open end of the bucket. Examples of pull-type bottom scrapers include scrapers disclosed in U.S. Pat. No. 4,383,380, U.S. Pat. Nos. 4,388,769, 4,398,363, 4,553,608 and U.S. Pat. No. 6,347,670 to Miskin.
However, for various reasons, the operator of the earth moving apparatus may need to more precisely control the unloading of the soil from the bucket or the time required to remove the soil from the bucket. For instance, loose soils, such as sandy soils, granular soils or dry soils, may readily flow out of the bucket when the bucket is tilted and the user may want to control the flow of the soil out of the bucket. In other instances, when the bucket is raised in a dump scraper, the soil may clump together and remain in the bucket until a large amount of the soil rushes out of the bucket all at once, thus hindering the ability of the user to control rate at which the soil exits from the bucket. In ejector scrapers, the time required for the ejector assembly to push the soil out of the bucket varies based on the power of the hydraulic system in tractors without high flow hydraulics.
Thus, a need exists for an improved earth moving apparatus that allows an operator to control the removal of the soil from the bucket.